In hospitals and labs, in order to create microscope specimens and the like from a tissue piece sampled from a living thing, a tissue piece treating apparatus for automatically performing each of treatments of fixing, dehydrating, degreasing, substitution of the tissue piece is used.
In a main body of the tissue piece treating apparatus, a treatment tank for performing each of the aforementioned treatments is provided. Moreover, a basket for accommodating the tissue piece is arranged inside the treatment tank.
In the tissue piece treating apparatus, a plurality of liquid chemical tanks storing each of the liquid chemicals used for treatment of the tissue piece in the basket and having different liquid chemical concentrations in order is provided. Moreover, a paraffin tank used for paraffin embedding is provided separately from the liquid chemical tanks.
Each of the liquid chemical tanks and the paraffin tank is connected to a rotary valve as a selection valve provided in the main body, and the rotary valve is connected to the treatment tank through an opening/closing valve.
Thus, each of the liquid chemical tanks and the paraffin tank can be connected to the treatment tank by being selected by the rotary valve.
Furthermore, the treatment tank can be brought into a pressurized or depressurized state by a pump, and when the treatment tank is brought into the depressurized state, the liquid chemical or paraffin can be supplied into the treatment tank from any one of the liquid chemical tanks and the paraffin tank selected by the rotary valve.
Moreover, the liquid chemical or paraffin brought into contact with the tissue piece having been supplied to the treatment tank and inserted into the basket is returned to the original tank by bringing the inside of the treatment tank into the pressurized state by the pump.
Since the rotary valve, the opening/closing valve, and the pump are controlled by a control unit, the tissue specimen can be sequentially subjected to immersion treatment with predetermined liquid chemicals and with the paraffin in accordance with a treatment order of the tissue specimen set in advance by the control unit.
In this tissue piece treating apparatus, in order to promote penetration of the liquid chemical to the tissue piece and substitution with a liquid contained in the tissue, concentration of the liquid chemical close to an interface between the tissue piece and the liquid chemical needs to be kept high.
Moreover, in the case of a tissue piece which is soft and has many gaps and tissue complicated in itself, if air bubbles enter a depth of the gap formed by the complicated tissue, the air bubbles cannot be removed easily, and the liquid chemical having entered into such gaps in a preceding process can remain without being drained in some cases.
Thus, the liquid chemical supplied into the treatment tank is agitated during the immersion treatment in order to keep the concentration of the liquid chemical close to the interface between the tissue piece and the liquid chemical high and to remove the air bubbles in the gaps of the tissue piece and liquid chemical in the preceding process.
Regarding the agitation of the liquid chemical in the treatment tank in the prior-art tissue piece treating apparatus, provision of a stirrer in order to agitate the liquid chemical by rotation of the stirrer or rotation of a sample basket itself accommodating the tissue piece have been examined, for example.
However, in the case of agitation using the stirrer, since the stirrer is driven by a magnet disposed outside the treatment tank through a wall surface of a bottom portion of the treatment tank, the driving force is poor, and since the stirrer can be provided only at a portion such as a bottom portion, a side wall or the like of the treatment tank, a sufficient amount of the liquid chemical cannot be agitated and moreover, since agitation can hardly affect a spot close to a center part of the treatment tank, sufficient agitation is not performed.
Moreover, in the case of rotation and agitation of the sample basket itself, since a rotary shaft is provided by protruding outward from a shaft hole provided in the bottom portion of the treatment tank, a seal structure of the shaft hole portion or the like is needed, which makes the structure complicated. Moreover, since an ordinary sample basket accommodates many tissue pieces, in a spot close to a center of the sample basket, even if the sample basket itself is rotated, the agitated liquid chemical cannot enter the spot close to the center part easily.
Thus, a tissue piece treating apparatus is proposed in which a pump and a valve are operated and a liquid supply/drain cycle is repeatedly performed in which a predetermined amount of liquid chemical is drained to a corresponding liquid chemical tank to such a degree that the tissue piece accommodated in the treatment tank is not exposed from the liquid chemical during a tissue piece treatment process in which the tissue piece is subjected to an immersion treatment in a liquid chemical in the treatment tank for a predetermined time, and after the predetermined amount of the liquid chemical is drained, the same amount of the liquid chemical is supplied into the treatment tank again from the liquid chemical tank so that the liquid chemical is agitated only by repeating liquid supply/drain of the predetermined amount of the liquid chemical supplied into the treatment tank (see PTL 1).
According to this tissue piece treating apparatus, agitation of the entire liquid chemical in the treatment tank can be reliably performed, and the agitation is possible with a simple structure without providing driving means such as a motor for agitation of the liquid chemical.